Rescue helicopters evacuated dozens of people from snow-blocked villages in Serbia and Bosnia and airlifted in emergency food and medicine as a severe cold spell kept eastern Europe in an icy grip.

The death toll from the cold snap rose to 79 across the region, with emergency crews working overtime as temperatures sank to -32.5C (-26.5F) in some areas.

Parts of the Black Sea froze near the Romanian coastline and rare snow fell on Croatian islands in the Adriatic Sea. In Bulgaria, 16 towns recorded their lowest temperatures since records began 100 years ago.

In central Serbia, helicopters pulled out 12 people, including nine who went to a funeral but then could not get back over icy, snow-choked roads. Two people froze to death in the snow while two others are missing, bringing the country's death toll to five.

"The situation is dramatic, the snow is up to five metres high in some areas, you can only see rooftops," said Dr Milorad Dramacanin, who participated in the helicopter evacuations.

One of the evacuees was an elderly woman who had fallen into a coma. She survived after being airlifted to hospital.

Two helicopters were also used to rescue people and supply remote villages in northern Bosnia.

"We are trying to get through to several small villages, with each just a few elderly residents," said Bosnian rescue official Milimir Doder. "Altogether some 200 to 300 people are cut off. We are supplying them for the second day with food and medication."

Some villages have had no electricity for two days and crews were working around the clock trying to fix power lines.

"The snow is about two metres high and we have cleared off paths that look more like tunnels," Doder said. "It is going well but if there is more snow coming, then the situation may get critical."

Ukraine reported 43 deaths, mostly of homeless people. The country's emergency situations ministry said 28 people had been found dead on the streets, eight died in hospitals and seven in their homes. More than 720 others were hospitalised with hypothermia and frostbite.

Authorities have deployed over 1,730 heating shelters across the country, handing out hot tea, coffee, boiled potatoes and pork fat – a traditional Ukrainian dish – to the homeless. Hospitals were told not to discharge homeless patients even if their treatment was finished to protect them from the cold.

The country's prime minister, Mykola Azarov, urged Ukrainians to stay vigilant, dress warmly and help each other in the face of the severe weather.

"I call on citizens, enterprises, organisations not to be indifferent, to support and protect those people who cannot help themselves in this difficult time," Azarov said in a statement. "We are one people."

His comments came after some experts suggested Ukraine's high death toll was linked to authorities' unwillingness and incompetence in dealing with the homeless.

Pavlo Rozenko, an expert on social policy with the Kiev-based Razumkov Centre, said Ukrainian authorities often suffer from the Soviet legacy of viewing the homeless as alcoholics, drug addicts and do-nothings who need to be punished instead of helped.

"The country doesn't know yet how to take care of its homeless," Rozenko said.

In Romania, six homeless people have died of hypothermia in the past 24 hours as temperatures plunged to -32.5C, the health ministry reported. Hundreds of others were sent to shelters to protect them from the extreme cold.

Twenty people have also died of hypothermia since last Friday in Poland.

Several schools across Hungary suspended classes, including one in the east that said it could not afford the high heating bills.

In Russia, temperatures fell to -21C in Moscow but only one person was reported to have died as a result of the cold.

Despite freezing temperatures, 50-year-old Gyorgy Schirilla said he would go ahead with his annual swim across the Danube on Saturday with no protective gear – a distance of 500m – in the northern Hungarian city of Vac.

"I'm not afraid of the challenge," Schirilla said. "This will be my 15th crossing. Two years ago … I had to fend off ice floes weighing several tonnes."

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